In a surgical operation represented by abdominal surgery, plastic surgery, neurosurgery or the like, there is a problem of adhesion between organs as one of complications after operation. This is caused from the phenomenon wherein, when normal tissues having received injury due to drying and oxidation are stitched to each other to be closed in the operation, in a process of being self-healed by healing of wound, an adhesion phenomenon, namely, conjugation of the tissues of organs to each other which essentially must not happen, may be caused. It is said that adhesion is caused at a high possibility in a surgical operation, the adhesion may lead to pain or complications causing a serious symptom such as ileus or sterility.
It is difficult to treat an adhesion once caused, with medicine. Further, ileus due to an adhesion may be caused even after several years have passed after an operation. It is believed that adhesion can be treated only by adhesion separation surgery which separates the adhesion part by conducting surgical operation again and, therefore, in a surgical operation, prevention of adhesions is extremely important.
So far, as the treatment to prevent tissue adhesion or delay of healing after operation, a method of covering an exposed organ tissue with a piece of gauze dipped in a saline to prevent drying and oxidation has been employed. However, because an organ has a complicated and flexible property, the method has been origins causing problems such as ones that a sufficient covering cannot be carried out by gauze, that gauze becomes an obstacle relative to performing the operation by the doctor, and that the possibility of leaving gauze in the body is increased because much gauze is used.
From such reasons, as the materials having an effect of preventing adhesion or preventing delay of healing, a method of using a silicone, “TEFLON” (registered trademark), a polyurethane, an oxycellulose and the like as an adhesion preventive membrane has been employed to physically separate origin tissues. However, because these materials are non-absorbent materials, they are left on the surface of the biological tissue, and not only do they delay repair of the tissue but also they become originators of infection and inflammation.
In recent years, to solve such problems, antiadhesive materials using gelatin or collagen that can expect bioabsorbability are reported (JP 2004-065780 A and JP 2001-192337 A). Further, an antiadhesive material using a polysaccharide such as trehalose which has no risk of infectious disease (JP 2003-153999 A) and an antiadhesive material using a hyaluronic acid (WO 2005/094915) are also reported.
However, in antiadhesive materials using gelatin or collagen as described in JP 2004-065780 A and JP 2001-192337 A, there is a problem where it is difficult to remove telopeptide part having an antigenicity and, further, because there is a risk of an animal-derived infectious disease such as prion contamination, it is better to avoid use to an organism. Moreover, there are many instances where a crosslinking agent added to obtain strength and control degradability is not preferred for use in an organism. Furthermore, in a natural polymer such as gelatin or collagen, there is such a problem that it is low in strength though it is high in affinity with skin. Therefore, in a natural polymer, although it is necessary to ensure a strength by a material crosslinked with a crosslinking agent or by use of a reinforcement material or by wrapping with a gauze, when a reinforcement material is used, because there are many instances where the structure becomes complicated, it is not practical.
Further, in an antiadhesive material using a polysaccharide as described in JP 2003-153999 A, the strength of a polysaccharide is poor, and there is a problem that suture is difficult because of lack of strength. Further, even if suture is possible, it is difficult to maintain a sutured state for a certain period of time.
Further, in an antiadhesive material using a hyaluronic acid as described in WO 2005/094915, because of its poor close adherence with an organ, the antiadhesive material and the organ are liable to be shifted from each other, and whereby an adhesion may be caused and, therefore, it is not always said that it has a satisfactory performance and, further, there is a problem that it is high in manufacturing cost because it is difficult to serve it to mass production. To solve these problems, although there are a method of using blood products and a method of using chemical substances to strongly bring the antiadhesive material into close contact with the organ and the like, these methods include a problem that high-quality management in viewpoints of hygiene and safety is required and it is difficult to be handled.
Furthermore, in the antiadhesive materials disclosed in JP 2004-065780 A, JP 2001-192337 A, JP 2003-153999 A and WO 2005/094915 (gelatin, collagen, polysaccharide, natural polymer, hyaluronic acid and the like), it is difficult to be adapted to use requiring a high mechanical strength (an affected part high in pressure load ascribed to a body fluid such as blood or an expiration).
Thus, although there are many reports relating to materials to prevent tissue adhesion, a material having a satisfactory performance (close adherence with an organ, mechanical strength) as an antiadhesive material has not been obtained. Namely, a material capable of preventing adhesion until a tissue is recovered and maintaining a strength until the tissue is recovered, without causing the above-described problems, is required.
Accordingly, in consideration of the background of such conventional technologies, it could be helpful to provide a polymer laminate excellent in biocompatibility and mechanical strength and also capable of containing chemicals and particles.